OFFICECODE | DATE | VAL
10200 | 2018-05-01 | 1
10200 | 2018-05-02 | 2
10100 | 2018-05-01 | 3
10100 | 2018-05-02 | 2

OFFICECODE | DATE | SUM(VAL)
10200 | 2018-05-01 | 1
10200 | 2018-05-02 | 3 (1+2)
10100 | 2018-05-01 | 3
10100 | 2018-05-02 | 5 (3+2)

SELECT
      A.OFFICELKD,
      A.DATE,
      A.VAL,
      @VAL := @VAL + A.VAL AS `VALSUM`
   FROM
      ( SELECT
              cur.OFFICELKD,
              cur.DATE,
              cur.VAL
           FROM
              tblReport cur
           LEFT JOIN
          tblReport pre
       ON cur.OFFICECODE = pre.OFFICECODE
       GROUP BY cur.ID
           ORDER BY
              OFFICECODE ) AS A,
      ( SELECT @VAL := 0 ) AS SqlA
   ORDER BY OFFICECODE, DATE